With Congress deep in debate over legislation aimed at the prevention of global warming, and skeptics ramping up their rhetoric, it seemed like a good time to take a step back to some basics — more accurate information is critical here. Step one in figuring in out how we can help in the battle against climate change involves answering questions like “What are the major causes of global warming?”
What causes global warming?
[social_buttons]Scientists have understood the greenhouse effect since the early 19th century; the first paper on the topic was published in 1896. Essentially, certain gases trap energy from the sun: according to the Intergovernmental Panel on Climate Change’s Fourth Assessment Report, greenhouse gases “act as a partial blanket for the longwave radiation coming from the surface. This blanketing is known as the natural greenhouse effect.”
What are greenhouse gases?
Several compounds contribute to the greenhouse effect, including
Carbon dioxide (CO2): Carbon dioxide is probably the best-known greenhouse gas. According the US Environmental Protection Agency, “Carbon dioxide enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., manufacture of cement)”
Methane (CH4): Methane is produced by the production and transportation of a number of fossil fuels, by livestock, and by the decay of organic materials. It is 20 times more potent a greenhouse gas than CO2.
Water vapor: Water vapor is the most abundant greenhouse gas, and skeptics have tried to use this fact to dismiss claims about atmospheric CO2 levels. The Christian Science Monitor noted earlier this year, though, that “As CO2 concentrations have risen and warmed the atmosphere, the warming has allowed the atmosphere to hold more water vapor, which in turn further warms the atmosphere.” RealClimate noted this fact several years ago, claiming that water vapor is a feedback, not a forcing.
Nitrous oxide (N2O): Nitrous oxide is produced largely by agricultural practices, as well as manure and sewage management.
Fluorinated gases (or High Global Warming Potential gases): This group of gases, which includes hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride, are “synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes.” Ironically, several of these compounds are used widely as substitutes for ozone-depleting substances.
What are the major sources of greenhouse gases?
While all greenhouse gases (except fluorinated gases) occur in nature, the EPA’s most recent Inventory of Greenhouse Gas Emissions and Sinks shows a 20% rise in emissions of CO2 from human sources over the study period of 1990-2004; methane and nitrous oxide emissions, fortunately, have decreased over this period. Among the most prominent sources of greenhouse gases:
- Fossil fuel combustion
- Cement production
- Incineration of wastes
- Agricultural soil management
If were going to prevent further global warming, understanding its sources, and our contributions to it, are critical. We can reduce our emissions of greenhouse gases while maintaining economic sustainability… let’s hope our leaders keep that in mind as they debate the path forward in addressing climate change.
Image credit: wburris at Flickr under a Creative Commons license
You should also introduce the readers to the notion of the bandwidth of light. CO2 can only trap light at a certain wavelength and has exponentially decreasing returns for warming.
They would also be better informed if they knew the catastrophic effects come not from the heat trapping of the CO2, but postulated positive feedback mechanisms that multiply the small direct effects of carbon dioxide.
@tehdude — thanks for the feedback… I mainly wanted to hit the highlights on the greenhouse effect and GHGs here… I definitely want to deal with the mechanics in another post.
The Solar Grand Maximum that has been going on for about 70 years has ended. The 30 year or so PDO uptrend that combined with the Solar Grand Maximum to produce the end-of-century temperature run up has started its 30 year downtrend. The PDO downtrend combined with the quiet sun is going to result in planet cooling. The sun has not been this quiet this long since 1913. The Climate Science Community appears to be unaware of the science (it’s not in their curriculum) which shows, using paleo temperature data, that added atmospheric carbon dioxide has no significant influence on average global temperature. See my pdf linked from http://climaterealists.com/index.php?tid=145&linkbox=true for the proof and to identify the missing science. Or email [email protected]
Yesterday and today the temperatures when I awoke at 5:00 a.m. were in the mid-50’s, approximately four (4) degrees warmer than the record lows set on these dates in 1945. Tomorrow, if the forecast holds true, it will happen again. Highs are in the mid-70’s. It is the second half of May in south Louisiana and I cannot remember it ever being this cool this late into the year. I know that my observations are anecdotal but something is amiss with the theories that all warming is manmade and attributable to a handful of “greenhouse” gases.
Even though the sun is experiencing its weakest solar cycle since 1928, if manmade gases are the only cause of global warming (a.k.a. climate change) then why are we approaching low temperatures not seen in 64 years? Come to think of it why was it so cool in 1945? Just prior to 1945, the world was impacted by two major events: The Great Depression and World War II. The Great Depression led Franklin Roosevelt to implement The New Deal, which created an unprecedented amount of make-work projects. According to the post, shouldn’t the millions of tons of cement produced to build FDR’s highways and dams have contributed to an increase in global temperatures by 1945? Since World War II was fought on a global scale, just consider the amount of fossil fuels burned and the tonnage of explosives set off during that period. Hitler’s Germany alone eliminated 6 million Jews and either buried the bodies in landfills or burned them in incinerators. Shouldn’t the war effort have led to an increase in global temperatures by 1945? How exactly did the greatest gains in industrial output up to that time in history lead to lower temperatures?
Now, I know that people smarter than you (i.e. Dr. James Hansen) and I (i.e. Dr. Roy Spencer) study the climate for a living. Yet, there is hardly a consensus that one side is correct and the other side is wrong. To say with impunity that the skeptic (thanks for not saying “denier”) is wrong or to label him a shill, is simply politicizing the issue. Are we really willing to alter the global economy over an unsettled issue?
@Bobby… I’ve started timing how long it takes you to respond… 😉
I’ll get back to your argument when I’ve got some time to respond thoughtfully…
Yesterday, I was in the mood to banter. I have other things to focus on today, but will try to check later for your reply.
BTW, I posted a very non-controversial reply to Gavin Hudson’s piece about green shaving over on “Feelgood Style.” Actually, I was somewhat supportive of his comments because (IMO) old-style wet shaving is an improvement over the modern alternatives; whether or not it’s any greener. I was surprised when it died in moderation. Thanks for keeping your blog open to the considerate exchange of ideas.
Whoops! I spoke too soon. It seems that my comments regarding a post dying in moderation were a bit hasty. My apologies to Gavin and the folks at “Feelgood Style” if any offense was taken.
I’m sure they’re fine with it… if it’s your first comment post there, it has to be moderated manually, and most of us do that once-twice a day…
Thanks Jeff – good information and resources for future consideration. I make not so nice comments when I believe a writer is being foolish and certainly must make a positive comment in this case.
To those who do not believe we are messing up the environment – I would suggest comparing emissions to peeing in the pool. When one does it it is not a big thing – when millions & billions do it the pool gets a bit nasty.
I believe in the warming scenario but I also believe the pool is becoming overloaded from many fronts. Getting out is not really an option so we need remedial actions rather urgently.
To remediate a swimming pool, you have but two options:
1. Drain it and refill it with fresh water.
2. Treat it with chemicals to destroy the “nasty” bits.
Since environmentalists are generally anti-chemical, how do you propose we drain and refill a planet? If the planet really was on the fringe of a global apocalypse, will it not drain itself naturally via mass instinctions and then eventually clean itself back up?
we should holds hands together to prevent global warming at its worst effects and to preserve the beauty of nature.
you forgot to mention water vapor makes up 95% of greenhouse gases
99.99% of that is from nature
omg. we should help post flyers around New York and work together to save the world. (sounds a little dramatic)